1. Field of the Invention
The present invention relates to a rendering control apparatus, a control method thereof, a recording medium, a rendering server, and a rendering system and, more particularly, to a technique of providing a rendered screen for a client device connected to a network.
2. Description of the Related Art
Client devices such as personal computers (PCs) connectable to networks are widely used. With the spread of these devices, the network population of the Internet is increasing. Recently, various services using the Internet have been developed for network users, and entertainment services such as games are also provided.
One of these services for the network users is a massively multiplayer type network game such as an MMORPG (Massively Multiplayer Online Role-Playing Game). In this massively multiplayer type network game, a user can perform a match-up play or team play with another user using a client device connected to a server for providing the game, by connecting his or her client device to the server.
In a general massively multiplayer type network game, a client device exchanges the data necessary to render the game with a server. The client device executes a rendering process by using received data necessary for rendering, and displays a generated game screen on a display device connected to the client device, thereby providing the user with the game screen. Also, information input by the user by operating an input interface is transmitted to the server, and used in calculation processing in the server, or transmitted to another client device connected to the server.
Unfortunately, some network games that perform a rendering process on a client device as described above require each user to use a PC having sufficient rendering performance or a dedicated game machine. Accordingly, the number of users of a network game (one content) depends on the number of users who own devices meeting the performance required by the content. That is, it is difficult to increase the number of users of a game requiring high rendering performance such as a game that provides beautiful graphics.
In contrast, as described in an International Publication No. 2009/138878, a game that a user can play without depending on the processability such as the rendering performance of a client device has recently been provided.
In the game as described in the International Publication No. 2009/138878, a server acquires information of an operation performed on a client device, and provides a client device with a game screen obtained by executing a rendering process by using the information. That is, when performing the rendering process on the server in response to an operation performed on the client device, it is necessary to increase the response speed, that is, rapidly provide a game screen reflecting the operation, in order to allow a user to play the game without any stress.
Especially in a massively multiplayer type network game, a server simultaneously generates game screens to be provided for a plurality of client devices. Therefore, it is desirable to reduce the time required for the rendering process of the plurality of game screens. However, the International Publication No. 2009/138878 does not mention any practical method of increasing the efficiency of the game screen rendering process.